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The results of a study of the optical properties of porous silicon nanostructures obtained by metal-assisted chemical etching of γ-quanta irradiated with low doses during their formation are discussed. The total reflection from the obtained samples depends not only on the irradiation dose of the forming layer, but also on the dose of preliminary irradiation of the initial silicon wafer by in situ control. By studying the Raman spectra of the samples, it was confirmed that changes in the spectra take place both due to the effect of small doses of γ-quanta on the initial silicon wafers and due to the in situ effect of gamma radiation on the forming SiNWs. We observed a shift in the wavelength of the photoluminescence maximum from 600 nm to 750 nm with a change in the irradiation of the initial silicon wafer from 0 to 40 kR at the same dose of irradiation of the forming porous layer.

Photoluminescent macroporous silicon is studied for tumor imaging application. Gamma-radiation is used for modification of morphology of pores and their size. It is shown by Raman and photoluminescence study that after the irradiation of gamma rays new nanocrystallites of smaller diameter in comparison to the initial porous silicon appeared.

The possibility of modifying the photoluminescence properties of porous silicon by irradiation with low doses of γ photons from a 226Ra radioisotope source and bremsstrahlung is demonstrated. The position of the longest photoluminescence wavelength tends to shift to the short-wavelength region of the spectrum. The emission efficiency increases upon irradiation of both the substrate and the layer formed.

A comparative study of the optical and morphological properties of different modifications of silicon and their dissolution upon interaction with distilled water and a biologically active medium is carried out. For the biologically active medium, nonpathogenic baker’s yeast (Saccharomycetes cereviseae) is chosen. It is shown that water and the biologically active medium interact with the surface of the materials and, thus, change the surface morphology and produce a modified layer. The strengths of the effect upon nanoparticles, nanoparticle-based structures (porous silicon), and single-crystal silicon doped with different types of impurities to different levels are different.

The possibilities of modifying the IR spectra of porous silicon under irradiation by low doses of gamma — quanta of radioisotope source of 226Ra and bremsstrahlung radiation are investigated.

In situ measurement of the formation process of low-dimensional porous silicon (PS) structures was developed. The measurements are based on the analysis of polyharmonic time dependence of the reflected radiation. The results show high sensitivity to H 2 S in PS based structures with catalytic (Pd, Ni) and ohmic (Al) electrodes. In the best samples the appearance of three molecules H 2 S on 10 9 molecules N 2 increased the electrical current value by a factor of 2–3. The structures selectively measure H 2 S concentration from 0.02 to 1000 ppm. It was found that unusually high reversible and nonreversible optical properties change because of the influence of gas solvents and alcohol. The exposure of PS layers to ethyalcohol vapor changes the color of PS from bright blue to crimson and the refraction coefficient in the IR region changes up to 0.06.